The Mangrove Ecosystem

Group No. IV

Vivek Iyer 201019Sanket V. Jagare 201020Yashvant Jain 201021Ishan Janabandhu 201022Nitin Kadam 201023Sandip Kadam 201024

• The word "Mangrove" is considered to be a combination of the Portuguese word "Mangue" and the English word "grove".

• Mangroves are salt-tolerant plants

• These are highly productive but extremely sensitive and fragile

• are breeding, feeding and nursery grounds for many estuarine and marine organisms

MANGROVES IN INDIA•According to a status report of the Government of India publication, the total area of the mangroves in India, was reckoned at about 6,740 sq.km.

•This covered about 7% of the world mangroves (Krishnamurthy, 1987) and 8% of the Indian coastline (Untawale, 1987).

•But a recent Indian Remote Sensing Data (Nayak, 1993) showed that the total area of the mangroves decreased to 4,474sq. km .

Functions & Benefits Of Mangrove:

• Natural habitat for endangered species

• Deposition of mud - With mangrove forests, marine water quality maintained from silt erosion.

• Nutrient enhancer - The physical properties of mangrove forests tend to slow the flow of water and precipitation occurs. - nutrients leaching from agricultural land, Benefits of mangroves are 25 fold higher than that of paddy cultivation.

• Sources of germ plasm.

Ecological Functions

• Carbon sequestration

- The process of change photosynthesis inorganic carbon (C02) into organic carbon in the form of vegetation material. - In most ecosystems, these materials decompose and release carbon back into the atmosphere as (C02). estimated that a loss of about 35% of the world’s mangroves has resulted in a net loss of 3.8 x 1014g C stored as mangrove biomass.

• Maintaining microclimate

• Prevent the development of acid sulphate soil

• Maintaining processes and natural systems

Screening the solar UV B radiation‐

The mangrove foliage produces flavonoids that serve as UV screen ‐compounds

Reducing the green house effects

Mangroves are known to remove CO2 from the atmosphere through photosynthesis.

The mangroves are capable of accumulating and storing carbon in the soil in large quantities.

They fix greater amounts of CO2 per unit area, than what the phytoplankton do in the tropical oceans

Minimizing the fury of cyclones

Mangrove forests protect all types of coastal communities from the fury ofcyclones and storms. The best example on finds is the super cyclone which‐occurred on the 29th October 1999 with a wind speed of 310 km hr 1 along the‐Orissa coast (India) and played havoc largely in the areas devoid ofmangroves. On the contrary, practically no damage occurred in regions withluxuriant mangrove growth.

Trapping the sediments

One of the important functions of mangroves is trapping of sediment, and thus acting as sinks to the suspended sediments .The mangrove trees catch sediments by their complex aerial root systems and thus function as land expanders.

Trapping and recycling of nutrients

Mangrove sediments have a high capacity for absorbing andholding heavy metals thereby preventing the spread of metal pollution in coastal areas. The sediments contain 90% of Mn and Cu released andalmost 100% of the Fe, Zn, Cr, Pb, Cd in the total ecosystem.

Besides fish,the mangroves support a variety of wildlife such as the Bengal tiger, crocodiles, deer, pigs, snakes, fishing cats, insects and birds.

Supporting the fishes and wildlife populations

Nearly 80% of the fish catches are directly or indirectly dependent on mangrove and other coastal ecosystems worldwide

Pichavaram mangroves alone nurture 30 species of prawns, 30 species of crabs, 20 species of mollusks, and 200 species of fish

Biomass and Litter ProductionMangroves contribute significantly to the global carbon cycle. Mangrove forest biomass may reach 700 t ha 1 ‐ (Clough, 1992) and Twilley et al. (1992) estimate the total global mangrove biomass to be approximately 8.7 gigatons dry weight (i.e. 4.0 gigatons of carbon).

Prevention of the coastal erosionThe mangrove systems minimize the action of waves and thus prevent the coast from erosion. This has been demonstrated in Vietnam. In the tall mangrove forests, the rate of wave reduction per 100 m is as large as 20% (Mazda et al., l997).

Another work has proved that mangroves form ‘live seawalls’, and are very cost effective as compared to the concrete sea wall and other structures for the protection of coastal erosion.

• Transportation• Recreation and tourism• Education and research

Economic Benefits

Economic Benefits• The mangroves supply forestry products (firewood, charcoal, timber, honeyetc.) and fishery products (fish, prawn, crab, mollusk etc.).

• mangrove twigs are used for making charcoal and firewood

• One ton of mangrove firewood is equivalent to 5 tons of Indian coal, and it burns producing high heat without generating smoke.

• Used as timber for its durability.

• Nypa leaves areused to thatch roofs, mats and baskets.

Facilitate apiculture

For instance, the Sundarbans provide employment to 2000 people engaged in extracting 111 tons of honey annually and this accounts for about 90% of honey production among the mangroves of India (Krishnamurthy,l990).

In Bangladesh, an estimated 185 tons of honey and 44.4 tons of wax are harvested each year in the western part of the mangrove forest.

Medicines

Bruguiera species (leaves) are used for reducing blood pressures andExcoecaria agallocha for the treatment of leprosy and epilepsy.

Extracts from mangroves seem to have a potential forhuman, animal and plant pathogens and for the treatment of incurable viral diseases like AIDS

• Protection against natural disasters

Mangrove sites in India

STATE/UT WISE MANGROVE COVER 2005 (Area in km²)

S. No State/UT Very Dense Mangrove

Moderately Dense Mangrove Open Mangrove Total Change w.r.t. 2003

assessment

1Andhra Pradesh

0 15 314 329 0

2 Goa 0 14 2 16 0

3 Gujarat 0 195 741 936 20

4 Karnataka 0 3 0 3 0

5 Kerala 0 3 5 8 0

6Maharashtra

0 58 100 158 0

7 Orissa 0 156 47 203 0

8 Tamil Nadu 0 18 17 35 0

9West Bengal

892 895 331 2,118 -2

10Andaman & Nicobar

255 272 110 637 -21

11Daman & Diu

0 0 1 1

12 Pondicherry 0 0 1 1 0Total

1,147 1,629 1,669 4,445 -3

Threats to the mangrove ecosystem

Natural Anthropogenic

• Climatic changes• Cyclones• Physical processes.

• Deterioration• Diseases• Pollution• Grazing• Agriculture, aquaculture• Human encroachment (including reclamation)

•Approximately 35% of mangrove area was lost during the last several decades of the twentieth century

• which encompass about half of the area of mangroves.[

• The United Nations Environment Program also estimated shrimp farming causes a quarter of the destruction of mangrove forests.

• Likewise, the 2010 update of the World Mangrove Atlas (WMA) indicated a fifth of the world's mangrove ecosystems have been lost since 1980.[42]

Most of the challenges to mangrove forests observed in Goa and the Middle Andamans are also relevant to other parts of India. These include both natural hazards and destructive human activities. However, the gravity of the problems varies from area to area.

Natural hazards•Cyclones, typhoons and strong wave action

•Browsing and trampling by wildlife

•Infestation by barnacles which attach to young seedlings, interfering with respiration and photosynthesis and delaying seedling growth

•Damage by oysters to the young leaves

•Crabs, which attack young seedlings, girdle the root collars

•Gastropods that eat young leaves and flowers of mangroves, a big problem in the Middle Andamans;

•Insect pests such as wood borers, caterpillars (which eat the mangrove foliage and damage the wood as well)

•Weeds such as Acrostichum aureum and Acanthus species, which often occupy deforested mangrove areas and restrict the regrowth of economic mangrove tree species;

• Tall nursery-grown seedlings should be used for planting,

Solutions :

• Mixed plantations

Problems caused by humans

•Indiscriminate tree felling and lopping, mainly for fuel wood, fodder and timber, especially in areas close to human habitation.

•indiscriminate conversion of mangroves on public lands for aquaculture human habitation and industrial purposes.

•lack of interest of private landowners (village communities and individuals) in conserving and developing the mangroves on their lands.

•Illegal large-scale collection of mangrove fruits, which hinders their natural regeneration

•Discharge of industrial pollutants into creeks, rivers.

•The traditional use of dragnets in fishing.

Problems caused by humans, can be traced to the following root causes

•the poverty of the local inhabitants, which forces them to depend on mangroves for their fuelwood, timber and fodder requirements even if collection is illegal;

•increasing population, resulting in more pressure on mangroves;

•lack of education and awareness regarding the importance of mangroves, and ignorance of rules and regulations regarding conservation of mangroves;

•improper planning of development activities such as aquaculture, agriculture, construction for human habitation, mining and industrial-ization;

•short supply of fuelwood, timber and fodder at affordable prices;

•absence of a systematic survey of the area and the ownership of the land under mangroves, facilitating encroachment on this land;

The government of Goa has already banned felling of 15 species of mangroves for a period of ten years under the Goa, Daman and Diu Preservation of Trees Act, 1984.

Mangrove conservation and development efforts undertaken by the Government of India, the Government of Goa and the Andaman and Nicobar Islands Administration have so far been successful in reducing the degree of problems, but there is scope for further improvement.

Directions of mangrove protection policy.

a) Mainstream the sustainable management of mangroves into the forestry sector regulatory regime, ensuring that they continue to provide livelihoods to local communities.

b) Disseminate available techniques for regeneration of coral reefs, and support activities based on application of such techniques.

c) Explicitly consider sea-level rise and vulnerability of coastal areas to climate change and geological events, in coastal management plans, as well as infrastructure planning and construction norms.

d) Adopt a comprehensive approach to Integrated Coastal Management by addressing linkages between coastal areas, wetlands, and river systems, in relevant policies, regulation, and programs.

e) Develop a strategy for strengthening regulation, and addressing impacts, of ship-breaking activities on humanhealth, and coastal and near marine resources.

It has been cited that mangroves can help buffer against Tsunami, cyclones, and other storms.

One village in Tamil Nadu was protected from tsunami destruction

-the villagers in Naluvedapathy planted 80,244 saplings to get into the Guinness Book of World Records.

- This created a kilometre-wide belt of trees of various varieties. When the tsunami struck, much of the land around the village was flooded, but the village itself suffered minimal damage.

Reforestation

In some areas, mangrove reforestation is also underway. Red mangroves are the most common choice for cultivation, used particularly in marine aquariums

Mangroves also appear in home aquariums, and as ornamental plants, such as in Japan.

In Senegal, Haïdar El Ali has started the Océanium de Dakar project, which (amongst others) focuses on reforesting several areas with mangroves.[47]

Programmes to raise people's awareness of the importance of mangroves, e.g. through films, exhibitions, newspapers, magazines, posters, stickers, brochures, banners, seminars, nature camps, birdwatching, study tours in the mangrove forests, establishment of mangrove parks in the mangrove areas close to towns, and the celebration of Mangrove Conservation Day, with essay competitions, debates and drawing competitions

Recommendati ons

•incentives for sustainable management of mangroves on private and village community land;

•enforcement of environmental protection laws;

•research on problems related to pests and diseases and on appropriate management of the mangrove ecosystem;

•restoration and rehabilitation of degraded mangrove areas.